Field of the Invention
The present invention relates to the technical field of liquid crystal display technology, and more particularly to an LCD array substrate, an LCD panel and an LCD pixel circuit.
Description of the Related Art
An LCD (Liquid Crystal Display) uses the change of electric field strength on liquid crystal molecules to change the orientation of the liquid crystal molecules so as to control the strength of light to display images. Currently, a liquid crystal display apparatus has been widely used in terminal display devices having any sizes due to its features of light-weight, small-volume and thin-thickness. An LCD is mainly formed by an array substrate and a color-filter substrate. The array substrate is provided with gate lines, data lines, pixel electrodes and thin-film transistors. Each of the pixel electrodes is controlled by the corresponding thin-film transistor. When the thin-film transistor is turned on, the pixel electrode is being charged during the turned-on time. After the thin-film transistor is turned off, the pixel electrode maintains its voltage until next scanning for recharging.
Due to a voltage coupling effect of the thin-film transistors, at the moment when an electric potential of a gate signal decreases from a high level, a pixel charging voltage will have a change of a voltage difference ΔV. ΔV means a feed-through voltage. In general, a feed-through phenomenon is a problem that a liquid crystal panel may often encounter. The existence of feed-through phenomenon will cause a brightness difference between a frame of positive polarity frame and a frame of negative polarity, and then cause the panel to have a flicker problem and increase the risk of image sticking. Therefore, the feed-through voltage needs to be reduced by all means when designing the panel. The influence of a feed-through phenomenon performed on the pixel electric potential may be referred to ΔV=(Voff−Von)·Cgs/Ctotal, wherein Voff and Von are a turn-off voltage and a turn-on voltage of a scanning line as shown in FIG. 1; Ctotal is the capacitor of the pixel electrode which generally includes three capacitors: Ctotal=Cgs (parasitic capacitor of a TFT)+Cst (storage capacitor)+Clc (liquid crystal capacitor). It can be seen from the foregoing formula that the value of ΔV can be lower by reducing Cgs or increasing Ctotal. Generally, the feed-through voltage is reduced by a way of increasing Cst. The larger Cst is, the less the amount of voltage coupling is. However, Cst is usually limited by conditions such as an aperture ratio and thus cannot be made larger.
Therefore, the conventional technologies still have defects, and require more improvements.